Atypical teratoid/rhabdoid tumor of the cerebellum: report of two infantile cases.

Atypical teratoid/rhabdoid tumor of the CNS is an aggressive infantile neoplasm of uncertain origin. In our two infantile cases, this tumor presented as a bulky cerebellar hemispheric mass with significant mass effect to the fourth ventricle and brain stem. Although the attenuation on CT and signal intensity characteristics at MR imaging of this tumor were similar to those of vermian medulloblastoma, cerebellar hemispheric location and aggressive growth pattern could be considered as different gross morphologic characteristics of this tumor. Despite intensive chemotherapy and radiation therapy, both of our two patients died within 8 months of pathologic diagnosis.